JPH0752051B2 - accumulator - Google Patents

Description

TECHNICAL FIELD The present invention relates to an oil return pipe of an accumulator used in a refrigeration cycle. More specifically, it relates to improvement of an accumulator provided between an evaporator and a compressor.

[Prior Art] FIG. 3 shows a cross-sectional view of an example of one generally used as a conventional accumulator of this type.

In FIG. 3, (1) is a tank, (2) is an inlet pipe through which the refrigerant and lubricating oil are guided from the evaporator, (3) is an outlet pipe that delivers the refrigerant and lubricating oil to the compressor, and (5). Is lubricating oil, (1
3) is an oil return hole, and (14) is a pressure equalizing hole. The refrigeration cycle including the evaporator and the compressor is well known and is not shown.

The operation of the conventional accumulator shown in FIG. 3 is as follows.

From the evaporator, the refrigerant and the lubricating oil are introduced into the tank (1) via the inlet pipe (2). Those in the liquid phase of the refrigerant are heated by the heat of penetration rather than the outside of the tank (1) and are completely vaporized. On the other hand, the lubricating oil (5) mixed in the refrigerant introduced from the inlet pipe (2) is separated from the refrigerant in the tank (1) and stored in the bottom of the tank (1). The outlet pipe (3) has a U-shaped curved portion in the tank (1), one end of which opens to an upper portion inside the tank (1) and the other end of which penetrates the top wall of the tank (1). It extends to the outside. A small-diameter oil return hole (13) is opened at the lowest point of the curved portion of the outlet pipe (3). Therefore, the lubricating oil stored at the bottom of the tank (1) flows into the outlet pipe (3) through the oil return hole (13), mixes with the refrigerant gas flowing in the outlet pipe (3), and enters the compressor. Sent out. Since both the refrigerant and the lubricating oil can be circulated in the refrigerant cycle as described above, continuous operation is possible without additionally charging the compressor with the lubricating oil.

Further, FIG. 4 shows a cross-sectional view of another example of the accumulator generally used in the past as this type of accumulator. In FIG. 4, (1) is a tank, (2) is an inlet pipe through which the refrigerant and lubricating oil are guided from the evaporator, (3) is an outlet pipe that delivers the refrigerant and lubricating oil to the compressor, and (4). Is a heat exchanger, (5) is lubricating oil stored at the bottom of the tank,
(7) is an oil return pipe, and (12) is a closing plate such as a restriction orifice provided inside the outlet pipe (3) and immediately before the oil return pipe connection hole. The refrigerant cycle including the evaporator and the compressor is well known and is not shown.

The operation of the conventional accumulator shown in FIG. 4 is as follows.

From the evaporator, the refrigerant and the lubricating oil are introduced into the tank (1) via the inlet pipe (2) and sprayed onto the heat exchanger (4). The heat exchanger (4) is provided at the bottom of the tank (1) in a coil shape, and a high-temperature refrigerant liquid supplied from a condenser (not shown) flows inside the coil. Therefore, what is in the liquid phase in the refrigerant is heated by the heat exchanger (4) and completely vaporized. On the other hand, the lubricating oil mixed in the refrigerant introduced from the inlet pipe (2) is separated from the refrigerant in the tank (1) and stored in the bottom of the tank (1). The outlet pipe (3) has a U-shaped curved portion in the tank (1), one end of which opens into the tank and the other end of which extends through the top wall of the tank (1) to the outside. . Then, one end of a thin oil return pipe (7) is connected to the lowest point of the curved portion of the outlet pipe (3). The refrigerant gas flowing in the outlet pipe (3) is compressed by the closing plate (12) provided immediately in front of the oil return pipe connecting hole to narrow the flow passage to increase the flow velocity, so that the pressure is higher than the internal pressure of the tank (1). Becomes low, and the differential pressure sucks up the lubricating oil (5) through the oil return pipe (7) and sends it to the compressor together with the refrigerant gas.

At this time, it goes without saying that the compressor sucks the lubricating oil little by little so that the compressor does not cause an oil hammer.

Further, Japanese Utility Model Laid-Open No. 56-54754 and Japanese Utility Model Laid-Open No. 61-27076 disclose the invention of an accumulator having a piping structure for taking out an oil return pipe for lubricating oil from the tank.
In these devices, the oil is returned to the outlet pipe above the liquid level in the accumulator by utilizing the pressure difference between the inside and the outside of the connecting portion of the outlet pipe and the oil return pipe.

[Problems to be Solved by the Invention] Since the conventional accumulator is configured as described above, when foreign matter is clogged in the oil return hole or the oil return pipe, the lubricating oil does not return to the compressor and the lubrication failure occurs. There was a risk of causing a serious accident. On the other hand, since the oil return hole and the oil return pipe are inside the accumulator and cannot be easily inspected and cleaned, there is a drawback that the accumulator needs to be replaced when the above problem occurs.

Further, in the apparatus shown in FIG. 3, the gas velocity in the outlet pipe during the minimum capacity control operation of the compressor must be such that the lubricating oil flowing into the pipe can be delivered to the outlet pipe rising head differentially.

Further, in the device shown in FIG. 4, it is necessary to select the same outlet pipe diameter as that of the device shown in FIG. 3 and the orifice diameter for lubricating oil suction, and the internal resistance of the outlet pipe increases when the compressor operates 100%. There was a problem that the refrigerating capacity inhibition rate increased and it was against the energy saving operation.

Further, it is necessary to select the gas outlet pipe diameter and the orifice diameter depending on the change of the capacity of the compressor and the operating temperature condition of the refrigerator, and there is a problem that the inexpensive product supply is hindered by standardization and sharing of the accumulator.

Further, in the devices described in Japanese Utility Model Publication No. 56-54754 and Japanese Utility Model Publication No. 61-27076, the pressure difference between the inside and the outside of the connection portion of the outlet pipe and the oil return pipe is fixed by the resistance of the pipe orifice. Therefore, there was a problem in ensuring the stability of oil return due to the increase and decrease depending on the gas velocity in the gas outlet pipe.

The present invention has been made in order to solve the above problems, it is possible to secure a stable oil return amount even with respect to the capacity control operation of the refrigerator and changes in operating temperature conditions, and with energy saving operation An accumulator that can easily perform cleaning, inspection work, and oil return amount adjustment work without replacing the accumulator even when oil return obstruction due to foreign matter occurs or when it is necessary to adjust the oil return amount. The purpose is to provide.

[Means for Solving the Problems] The present invention has an inlet pipe for introducing a mixture of refrigerant and lubricating oil sent from an evaporator into a tank, an outlet pipe for letting out a refrigerant gas inside the tank, and a bottom portion of the tank. An oil return pipe for supplying accumulated lubricating oil into the outlet pipe by its own weight effect of the lubricating oil surface, the oil return pipe being detachably connected to the tank bottom portion at one end thereof and the outlet pipe at the other end thereof. In addition, the present invention relates to an accumulator, which is detachably connected to the outside of the tank at a lowest position or a position lower than the lowest position of the tank.

An inlet pipe for guiding the mixture of the refrigerant and the lubricating oil sent from the evaporator into the tank, a heat exchanger provided in the tank for vaporizing the liquid-phase refrigerant in the tank, and a gas-phase refrigerant. An outlet pipe for guiding from the inside of the tank to the compressor, and an oil return pipe for supplying the lubricating oil accumulated at the bottom of the tank into the outlet pipe by the action of the self-weight of the lubricating oil, the oil return pipe, Removably connected to the bottom of the tank at one end and outside the tank to the outlet pipe at the other end,
The present invention relates to an accumulator, which is removably connected at a lowest position or a position lower than the lowest position of a tank, and is provided with a flow rate adjusting throttle valve and an automatic opening / closing valve in the middle of the oil return pipe.

That is, in the accumulator of the present invention, the oil return pipe is detachably connected to the bottom of the tank at one end thereof, and the other end of the accumulator is attachable to and detachable from the outlet pipe outside the tank at the lowest position or a position lower than the lowest position of the tank. The oil is returned to the bottom of the tank by the action of the weight of the lubricating oil surface.

Further, in the present invention, the accumulator has an oil return pipe removably connected to the tank bottom at one end thereof, and can be detachably connected to the outlet pipe at the other end outside the tank at the lowest position or below the lowest position of the tank. It is equipped with a strainer in the middle of the oil return pipe, a throttle valve for adjusting the flow rate, and an automatic opening / closing valve such as an electric valve that opens and closes the oil return pipe flow passage when the compressor stops operating. The oil is returned by its own weight.

[Operation] In the accumulator of the present invention, the amount of returned oil is adjusted outside the tank by the hole diameter and the pipe length of the oil return pipe detachably connected at the lowest position or the position lower than the lowest position of the tank. Returned to.

In addition, the oil return of the accumulator of the present invention is performed by the self-weight action of the lubricating oil surface at the bottom of the tank by the oil return pipe detachably connected at the lowest position or the position lower than the lowest position of the tank outside the tank. Oil is returned and the amount of oil returned is adjusted by operating the throttle valve. Further, an automatic opening / closing valve such as a motor-operated valve that opens / closes in conjunction with the stop of the compressor prevents the transfer of the lubricating oil into the suction pipe during the stop of the compressor.

[Example] The diameter of the oil return pipe provided in the accumulator of the present invention is not particularly limited, but when the flow control throttle valve is not provided in the oil return pipe, a desired oil return amount and The pipe diameter is selected so that

The piping shape of the oil return pipe may be any shape that allows piping at a tank bottom of the accumulator or a height lower than the bottom of the accumulator, and the oil return pipe can be easily attached and detached by attaching and detaching the connecting members at both ends. A removable shape is preferable.

As the connecting member, one that has been generally used from the past can be used without particular limitation.

Further, the flow rate adjusting throttle valve and the automatic opening / closing valve used in the accumulator of the present invention are not particularly limited,
Generally used throttle valves such as manual type, spring type, motor type, pneumatic type, spring type, solenoid type, motor type,
An on-off valve such as a pneumatic type or a hydraulic type can be used.

Next, an embodiment of the accumulator of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of the accumulator of the present invention.

In FIG. 1, (1) is a tank, (2) is an inlet pipe,
(3) is an outlet pipe having one end opened in the upper portion of the tank (1) and extending to the outside through the side wall of the lower portion of the tank (1),
(5) is lubricating oil, (6) is a connecting member attached to the bottom of the tank, (7) is an oil return pipe for guiding the lubricating oil (5) accumulated at the bottom of the tank (1) to the outlet pipe (3), Reference numeral (11) is a connecting member attached to the outlet pipe (3) outside the tank (1).

In the accumulator of FIG. 1 having the above structure, the mixture of the refrigerant and the lubricating oil from the evaporator is introduced into the tank (1) through the inlet pipe (2), and the liquid phase in the refrigerant is stored in the tank. It is heated and vaporized by the invasion heat from the outside of (1). The vapor phase refrigerant has a tank (1) at one end.
It flows into an outlet pipe (3) that opens inside and is sent to a compressor (not shown). Further, the lubricating oil (5) separated from the refrigerant in the tank (1) and accumulated at the bottom of the tank (1) flows into the outlet pipe (3) through the oil return pipe (7) due to the self-weight of the oil surface. Then, it is mixed with the refrigerant gas flowing in the outlet pipe (3) and sent to the compressor. The amount of oil flowing into the outlet pipe (3) is adjusted by the pipe diameter of the oil return pipe (7). If the oil return pipe (7) is clogged with foreign matter and the flow of the lubricating oil is disturbed, remove the oil return pipe (7) from the connecting members (6) and (11) and clean the inside. Cleaning or oil return pipe (7)
To replace. Alternatively, it is also possible to prevent the passage of the lubricating oil including the oil return pipe (7) from being clogged in advance by performing regular inspection. Since this maintenance and inspection can be performed without disassembling the tank (1), the work is easy.

In the embodiment of FIG. 1, the oil return amount is adjusted by the diameter of the oil return pipe (7), but an oil return amount adjusting throttle valve and a strainer may be provided in the middle of the oil return pipe. Good.

FIG. 2 is an explanatory view showing another embodiment of the accumulator of the present invention. In FIG. 2, (1) is a tank,
(2) is an inlet pipe, (3) is an outlet pipe that is open at one end in the upper part of the tank (1) and extends to the outside through the side wall of the lower part of the tank (1), (4) is a heat exchanger, (5) ) Is lubricating oil, (6)
Is a connection member attached to the bottom of the tank, (7) is an oil return pipe, (8) is a strainer, and (9) is an electrically operated valve that opens and closes the flow path of the oil return pipe (7) in conjunction with the compressor stoppage. , (10) are throttle valves for adjusting the oil return amount, and (11) are connection members attached to the outlet pipe (3) outside the tank (1).

In the accumulator of FIG. 2 having the above-mentioned structure, the mixture of the refrigerant and the lubricating oil from the evaporator is introduced into the tank (1) through the inlet pipe (2) and the heat exchanger (4).
Be sprayed on. The heat exchanger (4) is provided at the bottom of the tank (1) in a coil shape, and a high-temperature refrigerant liquid supplied from a condenser (not shown) flows inside the coil. Therefore, what is in the liquid phase in the refrigerant is heated by the heat exchanger (4) and completely vaporized. Then, the gas-phase refrigerant flows into the outlet pipe (3) whose one end opens into the tank (1),
It is sent to a compressor not shown. In addition, the lubricating oil (5) separated from the refrigerant in the tank (1) and accumulated at the bottom of the tank (1) has an oil return pipe (7), a strainer (8), and a motor-operated valve (9) due to the weight of the oil surface. The refrigerant flows into the outlet pipe (3) through the throttle valve (10), is mixed with the refrigerant gas flowing in the outlet pipe (3), and is sent to the compressor. The amount of oil flowing into the outlet pipe (3) is adjusted by the throttle valve (10). Even if foreign matter enters the oil return pipe, it is captured by the strainer (8), and the electric valve (9) that opens and closes in conjunction with the stop of the compressor causes the oil to return only when the compressor is in operation. The operation is easy because the oil return amount can be readjusted according to the combination with the compressors having different capacities and the operation result without opening the refrigerant circuit.

FIG. 5 is an explanatory view showing an embodiment of the accumulator of the present invention.

In FIG. 5, (1) is a tank, (3) is an outlet pipe having one end opened in the upper part of the tank (1) and extending through the lower wall of the tank (1) to the outside, and (11) is the tank (1 ) Outside the tank, the connecting member attached to the outlet pipe (3) at a position lower than the bottom of the tank, and other reference numerals are the same as those in FIG.

In the accumulator of FIG. 5 having the above structure, the lubricating oil (5) separated from the refrigerant in the tank (1) and accumulated at the bottom of the tank (1) is exactly the same as in the case of FIG. , Due to the self-weight of the oil surface, flows into the outlet pipe (3) through the oil return pipe (7), mixes with the refrigerant gas flowing in the outlet pipe (3), and is sent to the compressor. The amount of oil flowing into the outlet pipe (3) is adjusted by the pipe diameter of the oil return pipe (7). If necessary, the oil return pipe (7) is removed from the connecting members (6) and (11) and the inside thereof is cleaned, or the oil return pipe (7) is removed.
It is the same as in the case of FIG. 1 in that it can be easily replaced or the maintenance and inspection can be performed without disassembling the tank (1).

Furthermore, in the case of the embodiment shown in FIG. 5, even if the amount of oil in the tank (1) decreases and the oil level drops, the self-weighting effect of the head difference between the tank bottom and the connection part of the oil return pipe to the outlet pipe is secured. The operation can be continued as long as the oil remains in the tank.

An oil return amount adjusting throttle valve and a strainer may be provided in the middle of the oil return pipe.

FIG. 6 is an explanatory view showing another embodiment of the accumulator of the present invention. In FIG. 6, (1) is a tank,
(3) is an outlet pipe having one end opened in the upper part of the tank (1) and extending to the outside through the lower wall of the tank (1), and (11) is below the bottom of the tank outside the tank (1). Is a connecting member attached to the outlet pipe (3) at the position (1), and other reference numerals are the same as those in FIG.

In the accumulator of FIG. 6 having the above structure, the tank (1) is exactly the same as in the case of FIG.
The lubricating oil (5) separated from the refrigerant inside the tank (1) and accumulated at the bottom of the tank (1) is the oil return pipe (7), strainer (8), electric valve (9), throttle valve (10) ), Flows into the outlet pipe (3), is mixed with the refrigerant gas flowing in the outlet pipe (3), and is delivered to the compressor. The amount of oil flowing into the outlet pipe (3) is adjusted by the throttle valve (10). If foreign matter should enter the oil return pipe, it will be caught by the strainer (8), and the electric valve (9) that opens and closes in conjunction with the stop of the compressor will perform the oil returning operation only during the compression operation. The operation is easy because the oil return amount can be readjusted according to the combination with the compressors having different capacities and the operation result without opening the refrigerant circuit.

If the connection part of the oil return pipe to the outlet pipe is provided below the lowest position of the tank (1) as shown in FIG. 6, even if the oil level in the tank (1) drops, the tank bottom and the oil return pipe The head pressure difference with the connection to the outlet pipe is secured, and operation can be continued as long as oil remains.

[Effects of the Invention] As described above, according to the present invention, the oil return pipe is detachably connected to the tank bottom portion at one end thereof, and is connected to the outlet pipe at the other end thereof outside the tank from the bottom or the bottom of the tank. Since the structure is detachably connected at the lower position, even if the oil return pipe is clogged or the flow of lubricating oil in the oil return pipe becomes obstructed due to foreign matter, the oil return pipe only Cleaning and inspection are possible, the serviceability is improved without the need to replace or disassemble the tank itself as in the past, and the oil return pipe hole diameter can be changed when combined with compressors of different capacities. As a result, there is an effect that the oil return amount suitable for the compressor can be easily modified and the accumulator can be easily standardized.

Further, in the present invention, the oil return pipe is detachably connected to the tank bottom portion at one end thereof, and is detachably connectable to the outlet pipe at the other end outside the tank at the lowest position or a position lower than the lowest position of the tank. Since it is connected and equipped with a strainer, an electric valve, and a throttle valve, there is no clogging of the oil return pipe due to foreign matter, and the oil return amount can be adjusted without opening the refrigerant circuit. . The oil return method is also configured to return oil by the action of the oil surface's own weight at the bottom of the tank, so stable oil return can be performed even if there is a change in the gas flow rate in the outlet pipe due to capacity control operation and changes in operating temperature, and a stable refrigeration cycle. There is an effect that the operation can be performed and the accumulator can be easily standardized. Further, it is not necessary to secure the internal resistance of the pipe by an orifice for securing a differential pressure for returning oil, and there are effects such as improvement of refrigerating capacity and energy saving operation.

[Brief description of drawings]

1 is a side sectional view showing an embodiment of an accumulator of the present invention, FIG. 2 is a side sectional view showing another embodiment of an accumulator of the present invention, and FIG. 3 is a side sectional view showing an example of a conventional accumulator. FIG. 4 is a side sectional view showing another example of a conventional accumulator, FIG. 5 is a side sectional view showing another example of the accumulator of the present invention, and FIG. 6 is another embodiment of the accumulator of the present invention. It is a side sectional view showing an example. (Main symbols in the drawings) (1): Tank (2): Inlet pipe (3): Outlet pipe (4): Heat exchanger (5): Lubricating oil (6), (11): Connection member (7): Oil return pipe (8): Strainer (9): Motorized valve (10): Throttle valve

Claims (2)

[Claims] 1. An inlet pipe for introducing a mixture of refrigerant and lubricating oil sent from an evaporator into a tank, an outlet pipe for letting out a refrigerant gas inside the tank, and a lubricating oil accumulated at the bottom of the tank for the outlet. An oil return pipe for supplying by the self-weight effect of the lubricating oil surface is provided in the pipe, the oil return pipe is detachably connected to the tank bottom portion at one end thereof, and the outlet pipe is connected to the outlet pipe at the other end of the tank outside the tank. The accumulator, which is detachably connected at the lowest position or a position lower than the lowest position. 2. An inlet pipe for introducing a mixture of refrigerant and lubricating oil sent from an evaporator into a tank, an outlet pipe for introducing a gas-phase refrigerant from the inside of the tank to a compressor, and a bottom portion of the tank. An oil return pipe for supplying the lubricating oil into the outlet pipe by the self-weight effect of the lubricating oil, the oil return pipe being detachably connected to the bottom of the tank at one end thereof and to the outlet pipe at the other end thereof. It is detachably connected to the outside of the tank at a lowest position or a position lower than the lowest position of the tank, and a flow rate adjusting throttle valve and an automatic opening / closing valve are provided in the middle of the oil return pipe. Accumulator to do.